1. Field of the Invention
The present invention relates to a method of establishing range of somatic fat by Gaussian function approximation in computerized tomography which can automatically establish the range of somatic fat, which is used at the time of measuring the somatic fat by using the computerized tomography, using Gaussian function approximation by least square method.
2. Information Disclosure Statement
The importance of measurement of somatic fat has increased day by day in connection with fatness, and various methods of measurement of somatic fat have been suggested and used.
Although a method of measuring fatness degree by using ratio of height and weight is well known, it has a disadvantage that the correlation of ratio of height and weight with the amount of actual somatic fat is not strong. In addition, there is a method of measuring the amount of somatic fat by measuring conductivity, however, it has a disadvantage that accuracy is low since a deviation of the conductivity is large according to the measurement method. Further, there is a method of measuring ratio of waist circumference and hip circumference, however, it has a disadvantage that the correlation of the ratio of waist circumference and hip circumference with the actual amount of somatic fat is not strong. Still further, there is a method of measuring thickness of subcutaneous fat by pliers, however it has a disadvantage that the degree of precision is low since the method itself is very simple and can not directly measure the amount of somatic fat.
Recently, ratio of subcutaneous fat and intra-abdominal cavity fat is used as an indication of disease connected with the fatness, and a method of separately measuring the subcutaneous fat and intra-abdominal cavity fat is required. The computerized tomography is a means which satisfies such requirement and can separately and directly measure through an image processing the amounts of subcutaneous fat and intra-abdominal fat from computerized tomography image.
The computerized tomography provides an image composed of Hounsfield values proportional to density. The Hounsfield value for the air is -1000 and that for the water is 0. Further, the Hounsfield value for a material of high density such as a bone is 1000.
The method of measuring the somatic fat from the image composed as described above is a method in which a range of Hounsfield values corresponding to the somatic fat is given and the number of pixels belonging to the range is counted.
However, there is no standard range since a reference for the range of somatic fat is vague and different ranges of somatic fat are used depending on person. In addition, since the characteristic of somatic fat varies with person and region, different range of somatic fat have to be given, however, up to now, the same value has been used in the measurement of various persons and various regions.